In OFDM communications, such as communications based on the Very-high-bit-rate Digital Subscriber Line 2 (VDSL2) technology as defined in the ITU-T G.993.2 standard, the concept of bandplan is adopted. A bandplan is a plan for using a particular band of radio frequencies of a portion of the electromagnetic spectrum. A bandplan defines the operation frequency range and contains several groups of consecutive sub-carriers designated either to the upstream direction or the downstream direction. For point-to-point fiber-to-the-distribution-point (Fttdp) applications where crosstalk management across loops is not required, the bandplan is typically not required to be fixed. In these applications, guaranteeing a certain service rate and/or maintaining a desired upstream/downstream ratio tend to be of the highest priority. For example, a service provider may plan to provide a 200 Mbps downstream and 50 Mbps upstream rates at 100 meters to its customers. Although the aggregated data rate with the VDSL2 30a technology should be sufficient, it is not guaranteed that all subscribers will get 200 Mbps/50 Mbps rates with a fixed-bandplan approach due to variations in loop length, in-house wiring, etc.
To mitigate this problem, there is a need for a mechanism that allows a VDSL2 transceiver unit at the central office unit (VTU-O) to dynamically change bandplan based on the result of channel estimation.